Fuel tank cleaning system

ABSTRACT

The fuel cleaning system of the present invention includes removal of water and sludge which is accomplished using a gravity separator with a mist extracting means utilizing a large commercial cartridge type filter. The filter removes particles larger than 20 microns plus any water that was not removed in the gravity separator. Clean fuel from the filter is discharged at the bottom of the fuel tank at high velocity through a small opening. This agitates the water and sludge. The suction side of the system is located approximately one inch above the high velocity discharge where it picks up the water and sludge for removal by the separator and filter sections. During the process, water and sludge are drained from the separator and filter as accummulated. The system is powered by an explosion-proof electric motor driving a pump which handles approximately 5 gallons per minute.

This is a division, of application Ser. No. 899,071, filed 08/21/86,U.S. Pat. No. 4,772,401.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The system of the present invention relates to fuel tanks. Moreparticularly, the present invention relates to a system for cleaning afuel tank of a vessel such as a boat, or for cleaning an undergroundstorage tank, construction equipment, or other types of vehicles. It mayalso be used in conjunction with maintaining the fuel in a vessel cleanby placement intermediate the fuel tank and the engine of the vessel.

2. General Background:

One of the most difficult problems in the burning of liquid fuel such asdiesel fuel or gasoline in large quantities such as on board vessels,ships, boats, or for use in other settings such as gas diesel drivengenerators, is the accumulation of debris over a given period of timewithin the tank, and the presence of that debris in the fuel that isbeing utilized by the engine in that system. Of course, this debris orother type of contamination is detrimental to the overall operation andcontinued life of the engine, and creates difficulty in maintaining thesmooth running of the engine during the use of it.

In an effort to rectify this problem, systems for cleaning fuel tankshave included the removal of water and sludge from the fuel through theuse of various means. For example, a concentric suction--dischargearrangement has been used in drilling operations for many years;likewise gravity separators and cartridge filters are used in manydifferent applications in the industries. However, the use of acartridge filters as a direct filter means of cleaning of diesel is avery expensive proposition, in view of the fact that the major sludgefound in diesel or the like fuel begins to clog up a cartridge filtervery quickly, and therefore the filter must be changed quite often. Thisof course leads to much expense in the operation.

In U.S. Pat. No. 3,362,534 entitled "Fuel Water Separation Method AndApparatus", issued to Guenterl.Kay presents a system which is part of afuel supply system included with a diesel engine power plant whichsystematically and continuously should remove contaminants to assure aclean fuel supply to the engine. The '534 patent relates to theseparator within the system, with the separator and the filter operatingon a vacuum. In the system under the '534 patent, there is no agitationof the fuel in the tank; consequently the bottom of the tank below thesuction is not agitated at all, except when the fuel level is very low,and in such an event many fuel cleaning systems included in engineinstallations, do, in fact, become plugged when dealing with unusuallyhigh level of contaminants.

There is known in the art a system utilized by Papworth Industries alsofor cleaning fuel in a tank. The Papworth system operates on a vacuum.The pumping unit and filter is a self-contained unit which is locatedremotely from where the suction/discharge similarly enters the tank. ThePapworth system cleans the fuel with a self-contained single filteringunit in which the first step is for the fuel to pass over foampre-filter. Thus, 100% of the fuel and contaminants pass over the foampre-filter and at some point the unit must be shut down to remove thecontaminants. In the Papworth unit the second stage is a coalescentshroud which is designed to move water. The final filtration step in thePapworth unit is through a stainless steel filter element which is builtinto the system.

Other patents which are pertinent in the art include the following aslisted:

    ______________________________________                                        PATENT NO: INVENTOR:   INVENTION:                                             ______________________________________                                          938,495  Lunstrum    "Air Blue Blower"                                      2,846,710  Haka        "Tool For Cleaning Bend                                                       Bores"                                                   404,425  Obenchain   "Boiler Cleaning Apparatus"                            3,171,807  Neuman      "Liquid Separating                                                            Apparatus"                                             4,135,946  Casey, et al                                                                              "Process And Apparatus For                                                    Enchancing Growth Of                                                          Precipitables In A Chemical                                                   Solution"                                              3,900,397  Bell        "Fuel Tank Filter"                                     ______________________________________                                    

SUMMARY OF THE PRESENT INVENTION

The system of the present invention solves the shortcomings in the artin a simple and straightforward manner. The fuel cleaning system of thepresent invention includes removal of water and sludge which isaccomplished using a gravity separator with a mist extracting means inseries with large commercial cartridge type filter. The filter removesparticles larger than 20 microns, however, may be used in filtercartridges which have the ability to clean fuel up to 1 micron, ifrequired, plus any water that was not removed in the gravity separator.Clean fuel from the filter is discharged at the bottom of the fuel tankat high velocity through a small opening. This agitates the water andsludge. The suction side of the system is located approximately one inchabove the high velocity discharge where it picks up the water and sludgefor removal by the separator and filter sections. Fuel in the tank iscontinuously circulated through the system. During the process, waterand sludge are drained from the separator and filter as accumulated. Thesystem is powered by an explosion-proof electric motor driving a pumpwhich handles approximately 5 gallons per minute, but may be utilizedwith a unit which can handle 11.5 gallons per minute.

The system operates under pressure with the pumping unit being portableand located next to the tank access opening. This allows the equipmentoperator to continually monitor the pumping unit and shut it down ifnecessary. There are two hoses from the separated filter (1 supply hoseand 1 return hose), each being approximately 50 feet long.

The first stage of the system is the fuel cleaning stage utilizing agravity separator. This makes it possible for the heavy sediments tosettle by gravity to the bottom of the separator tank where they can bedrained off while the system is in operation. The contaminants whichsettle out in this stage are a very substantial portion of the totalcontaminants and may never go through the filter medium which requirescleaning. As a result, it is not necessary to shut the system downduring the job to clean or change out the filter components.

In the present system, the discharge side of the separator is packedwith steel wool which serves as a coalescent means and a rough filterfor the solids which did not settle out in the gravity separator. In thepresent system, a standard commercial filter processes and cleans thefuel which is discharged from the gravity separator filter coalescent.The particular filter used in this system is a Facet series 21 filter.There are several different types of filter elements which are availablefor use in the unit with various micron rating and water removalcapabilities.

In the present system, the pumping unit is independent of the fuelcleaning facilities. The complete unit consists of two identical fuelcleaning units (gravity separator plus cartridge filter), and necessaryhoses. The present system of the separator and the filter operates onthe pressure rather than the vacuum. In the system, sediments in thetank are purposely agitated by the suction/discharge assembly so thatthe heavy sediments can be removed periodically. This way the installedfuel filter equipment when the engine installation is not overloaded andshut down by heavy contaminants.

In summary, in the preferred embodiment of the system, there is provideda first separator tank including an inlet means for allowingcontaminated fluid to be pumped within the tank, a means within the tankfor circulating the fuel so the centripetal force within the tank forcesthe heavier solids out against the wall of the tank for falling to thebottom of the tank during the process. Further, there is included aninitial floor baffle plate wherein the solids which have gathered alongthe wall of the tank move to the very bottom of the tank where they aredischarged through a discharge port from the main body of the fuel. Asthe fuel is circulated, there is included a second baffle plate locatedabove the inlet line having a centrally located orifice, wherein thefuel moves upward through an initial filtering means such as steel woolor the like where the contaminant which were not separated out of thefuel in the separator portion are filtered through the first filtermeans. The fuel is then flowed to a second, secondary filter means,which filters out to a size up to 20 microns. Filter cartridges areavailable which can clean the fuel to 1 microns if to required. The fuelis then flowed to a second segment which filters out up to a size 20microns. However, a filter cartridge could be utilized which wouldfilter up to 1 micron in size if necessary. Then the fuel, beingrelatively clean is returned into the return line to the bottom of thetank. This is in effect a closed loop system with the fuel within a tankbeing circulated throughout the separator and filter means a number oftimes until the entire body of fuel within a tank has been cleaned.

An additional embodiment of the present invention would provide a tankincluding a downward depending baffle wherein fuel is injected at theupper portion of the baffle, fuel is required to move below thelowermost point of the baffle where the heavier contaminants within thefuel, such as solids and water, are then moved through a lower screenportion and removed from the tank through a drain line. The fuel is thenmoved up into the second portion beyond the baffle where it meets withthe initial filter medium such as steel wool or the like where thesecondary components are filtered out, and then are discharged into asecondary filtration means where the remaining components (again up to20 or less micron size) is filtered out and returned into the tank viainlet line.

Additionally, the preferred embodiment utilizing the cylindricalseparator tank could be utilized in conjunction in a fuel line between afuel tank and an engine whereby all fuel moving from the fuel tank tothe engine could pass through the separator and primary filter meanscontained within the separator tank for assuring cleaner fuel within theline than would be present without such filtration unit therein.Utilized in this mode, the separator will perform satisfactorilyoperating under pressure or a vacuum. What is accomplished is reducedchange out of filter castings with resulting lower cost.

Therefore, it is the primary object of the present invention to providea fuel cleaning system utilizing a primary separator tank and primaryfilter contained within a vessel;

It is a further object of the present invention to provide a fuelcleaning system which is operated under pressure as opposed to a vacuumsystem;

It is a further object of the present invention to provide a system sothat there is constant agitation within the fuel tank to assure that theheavy sediments can be removed periodically;

It is still a further object of the present invention to provide aportable system which can be utilized to clean fuel within a tank sothat the engine will perform satisfactorily thereafter using the normalfuel filter included with nearly all engine installations;

It is a further object of the present invention to provide a cleaningsystem utilizing a gravity separator as a first stage in the fuelcleaning process and a primary filtration means as the principal secondstage of the process in the cleaning system.

It is a further object of the present invention to provide a fuelcleaning system utilizing a gravity separator which due to the flow ofthe fuel into the separator creates a central low pressure zone and aperipheral high pressure zone to facilitate the movement of the fuel atthe upper level of the separator into a filtration zone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the preferred embodiment of the apparatus ofthe present invention;

FIG. 2 is an overall perspective view of the preferred embodiment of theapparatus contained in the system of the present invention;

FIG. 3 is an overall schematic view of the operation of the system ofthe present invention; using a second embodiment of the apparatus of thepresent invention

FIG. 4 is a detailed view of the suction and discharge lines in thesystem of the present invention; and

FIG. 5 is an overall view of the preferred embodiment of theseparator/filtration tank utilized in a fuel line.

PREFERRED EMBODIMENT OF THE PRESENT INVENTION

The system of the present invention is illustrated in the schematicillustration in FIG. 3 by the numeral 10. What is provided in thatillustration is a fuel tank 12 of the type contained upon a vessel suchas a ship or the like, which would in most instances contains a fuelsuch as gasoline, kerosene, or diesel fuel, of quantities up tothousands of gallons at a time. What is provided initially as seen inthe cross section of tank 12 is a suction line 14 having therewithin areturn line 16. The suction line 14 will be utilized for sucking fuelfrom the tank portion due to the action of pump 18 along the line withpump 18 moving the fuel contaminants along line 14 into the nextcomponent of the system. A second component of the system as seen inFIG. 3, would be a gravity separator 120 of the type as will beillustrated further, wherein the fuel is allowed to move through gravityseparator 120, wherein contaminants such as sludge or water containedwithin the fuel would move to the bottom of the gravity separator 120and be discharged from a discharge line, 123 and the remainder of thefuel would move through a primary filter 156 contained within thegravity separator vessel, out of line 27 into a secondary filter 34through a return line 16 to reenter tank 12 at a velocity which wouldkeep the fuel within tank 12 thoroughly agitated as seen by Arrows 31.This closed loop system 10 would be utilized in the cleaning of the tank12 and would allow the circulation of the fuel up to three to five timesthrough the system in order to guarantee cleaning of the fuel.

Although we have described the overall operation of the system as seenin FIG. 3, reference is now made to the specific illustrations of thecomponents of the system, the primary component being the gravityseparator/primary filter as will be illustrated by the numeral 20 inFIG. 1. It should be noted that although FIG. 3 illustrates separator120 in the system, the preferred embodiment utilizes separator 20 asseen in FIG. 1. Both separator 20 and 120 are easily interchangeable foruse in the system.

Separator 20 as seen in FIG. 1 is the preferred embodiment and includesa closed cylinder 22 having a continuous side wall 23 and a concavefloor portion 24, a convex top portion 25, together defining acontinuous closed tank 26 for use as a gravity separator/filtrationcomponent 20. As seen in FIG. 1, separator 20 contains an inlet line 28entering into the upper portion of its continuous side wall 23, line 28moving contaminated fuel via pump 18 (FIG. 3) into tank 26, as will bediscussed further.

In addition, separator 20 further includes an upper discharge line 27which would be primarily responsible for discharging fuel that hasundergone primary filtration and separation within tank 26.

Turning now to the internal structure and functioning of separator 20 asseen in FIGS. 1 and 2, reference is made to inlet line 28 which is seenin the drawings. Upon entering through wall 23 of tank 24, inlet line 28follows a short distance along the interior curvature of the wall 23with its exit point 29 substantially following the curvature of the wall23, and preferably, sloping down at a 10 degree angle to facilitate themovement of the heavy contaminants down into a discharge line 41.Therefore, as fuel enters line 28 as seen particularly in FIG. 2, thereis provided a swirling action of the fuel (Arrows 32), within thatportion of tank 26 that will be defined as a gravity separator zone 51,with the larger contaminants as indicated by dots 31 within the tanktending to move towards the wall 23 of the tank due to centripetal forcewhile the fuel is being moved therethrough. Following the movement ofthe contaminants to substantially the interior wall 23 the gravityeffect on the contaminants would tend to force the contaminants in thedirection of arrows 33 to the lower portion of the tank. The lowerportion of tank 26 further includes a convex baffle 35, which wouldcover a substantial portion of the concave floor portion 24 of tank 26,except for a flow space 37 between the end of circular baffle plate 35and the wall 23 of tank 26. It is in this flow space 37 that thecontaminants 31 would move to substantially the lower central collectionzone 39 wherein there is provided a contaminant discharge line 41 havinga valve 43 so that upon opening of valve 43 the heavy contaminants suchas sludge or water are discharged from the bottom of tank 26 as seen byarrow 45. What is provided in the substantially upper portion of tank26, which is that portion in the vicinity of inlet 28 and above inlet28, is fuel which is substantially free of the larger contaminants andthe heavier water. For purposes of function, it should be noted thatthere is an additional, circular, upper baffle plate 50 making contactwith the inner face of circular wall 23 to form a continuous innerbaffle having a central orifice 52 therethrough so that fuel may moveupward into an upper filtration zone 54 of the tank 26. The baffle 50serves the function of preventing any initial flow of the contaminatedfluid which is discharged from line 28 from entering the filtration zone54, i.e., that area above plate 50, causing the contaminated fluid toremain within the gravity separator zone 51 of tank 26. Upper baffleplate 50 is also on a substantially downwardly depending decline towardsport 52 so that should any large contaminants 31 either filtration zone54 they would in all likelihood move downward towards central port 52and into the gravity separator zone 51, i.e., that area below baffleplate 50, for ultimate discharge from discharge line 41.

Following the entry and the fuel which is substantially free from thelarger contaminants of water into the filtration zone 54, there isprovided a primary filtration means 56 which, in the preferredembodiment, includes a primary filtration medium 57 of wire mesh of thetype which would be confined within a basket 58 and positionedintermediate the upper baffle plate 50 and the exit line 27 so that allfuel exiting the filtration zone 54 through the top portion 25 of tank24 would filter through the primary filtration medium 56 prior toentering discharge line 27. For purposes of use, the primary filtrationmedium 57 would be provided to further remove any contaminants that hadnot been removed within the separator zone 51 of the tank, and wouldtherefore substantially remove any large contaminants or droplets ofwater contained in the fuel. Following the entrance of the substantiallyclean fuel into line 27 there is provided a second filtration member 34where there is undergone a secondary filtration, for any contaminants ofa size greater than 20 microns, and is a standard type of filtercartridge element so found in the art. Following the flowing of the fuelthrough filter 34 the fuel is then routed into return line 16 which thenreturns the fuel into tank 12 at a velocity in order to maintain thefuel within tank 12 agitated so that it may undergo additionalfiltration through the process.

Further, it should be noted in the gravity separator tank 26, that withthe entry of the contaminated fuel through inlet line 28, the movementof the fuel around the inner wall 23 due to the centripetal force as itenters the tank 26, creates a low pressure zone within the centralportion of the tank 26, and a high pressure zone around the exteriorinternal wall 23 of tank 26. This would facilitate the movement of thefuel out of which the large contaminants have been removed due togravity, upward into the filtration zone 54 for further treatment.Further, it should be noted that for purposes of construction, that theflow diameter of entry pipe 28 is approximately 1/2 inch, the diameterof centrally located orifice 52 in the interior of baffle 50 isapproximately 5 inches, since the exit point of the fuel from thefiltration zone 54 is also 5 inches. The exit line 27 is approximately 1inch in diameter.

In the second embodiment of the apparatus, it should be noted that thealternative embodiment would work substantially identically to thepreferred embodiment with the exception of the separator tank, which inthe embodiment designated as tank 120, as seen in FIG. 3. Tank 120 inthis particular embodiment is substantially a tank having four sidewalls 122, a top portion 124, and a flat bottom portion 126, alldefining an interior separator-filtration zone 130 there within.Further, it is seen that there again is an entrance line 28 through topportion 124 to define a first, separator zone 134. There is includedwithin zone 134 a plate 135 whereby contaminants in fuel 129 enteringtank space 130 are forced upward (Arrows 137) and begin settling. Thereis also provided a vertical baffle 136 which substantially separates theinterior 130 of tank 120 into first, separator zone 134 and a filtrationzone 138. The fuel, after entering separator zone 134, flows in the flowspace 140 below the end portion of baffle 136 and a screen member 148adjacent the bottom portion 126 of the tank 120. As the fuel flowsthrough flow space 140 the larger contaminants and water remain at thebottom 141 of zone 130 and are hopefully discharged beneath screen 148via discharge line 123. The fuel is than routed up portion intofiltration zone 138 where it encounters the primary filtration medium156 of the type utilized in the preferred embodiment, the filtrationmedium positioned intermediate the filtration zone 138 and the exit line27. Following the primary filtration of the fuel, the fuel exits theseparator tank 120 and again is routed into a secondary filter 28 whereagain secondary filtration of all solids and contaminants of 20 micronsor smaller depending on the type of secondary filter 28, will takeplace. The fuel then flows through return line 16 into tank 12. Again,this system is utilized on a closed loop containing basis until allcontaminants within the fuel contained in tank 12 have been removed.

FIG. 4 illustrates in detail the configuration of suction line 14housing smaller return line 16 within tank 12. As seen in FIG. 3 and 4,suction line 14 receives contaminated fuel 29 at a point adjacent thefloor 13 of tank 12. So that suction line 14 may be positioned there,return line 16 is provided with an elbow turn 17 as it exits the end 19of suction line 14, so that its exit is flush with end 19, yet itextends outward parallel floor 13 of tank 12 so that fuel returning anddischarged create a greater turbulence (Arrows 15) within tank 12 at thebottom where the greater amount of heavy contaminants are contained andwhich can therefore be sucked up by line 14. In addition, line 14 has aplurality of ports 18 on its lower end portion to assist in suctioningup the fluid from tank 12.

In comparison, it should be noted that the secondary system as seen intank 120 in FIG. 3 of the present invention does not utilize a swirlingor centrifugal effect to remove the contaminants as with the preferredembodiment, more readily utilizes more of a gravity type separationmeans for the contaminants as they are forced into the lower portion ofthe separator tank 120 in order to pass through the flow space 140. Theheavy contaminants would tend to remain in the lower portion of the tank120 for removal.

For purposes of cleaning separator 20 there is provided a cap member 60which is threadably contained on the top portion 25 of tank 26. Uponremoval of tap member 60, the filter medium 57 may be pulled from thecontainer basket 58, cleaned and returned into basket 58 for reuse.

For purposes of use, as seen in FIG. 5, a component of the system, i.e.,the separator can be used in conjunction with a fuel system wherein theseparator 20 would be positioned in the fuel line 150 intermediate adiesel tank 152, secondary filter unit 153 and the engine 154.Therefore, any fuel flowing between the diesel tank 152 and the engine154 would be forced through separator/ filtration unit 20 where theseparation of solids of the primary filtration through the filtrationmedium 57 would take place, prior to the fuel flowing to secondaryfilter 153, where smaller micron size contaminants are removed, and thenreentering fuel line 150 on its way to the engine. This way, theseparator/filtration system 20 could be utilized in conjunction with aconstant separation and filtration of the fuel in the fuel line 150other than with the cleaning system with the present invention.

Because many varying and different embodiments may be made within thescope of the inventive concept herein taught, and because manymodifications may be made in the embodiments herein detailed inaccordance with the descriptive requirement of the law, it is to beunderstood that the details herein are to be interpreted as illustrativeand not in a limiting sense.

What is claimed as invention is:
 1. A vessel for separating solidcontaminants and free water from contaminated fuel, the vesselcomprising:a. an annular wall portion, and top and bottom portions,together defining a vessel chamber therewithin; b. an upper horizontalbaffle member having a fluid flow bore therethrough, contained withinthe vessel chamber for separating the vessel chamber into a lowerseparator zone and an upper filtration zone; c. inlet means forintroducing contaminated fuel within the lower separator zone so thatthe fuel is circulated within the lower separator zone to cause largercontaminants and free water to move downward along the annular wall ofthe vessel chamber into a lower portion of the separator zone; d. lowerbaffle means within the lower portion of the separator zone of thevessel chamber for preventing free water and contaminants that havesettled within the lower portion of the separator zone from returninginto an upper portion of the separator zone; e. means within the lowerportion of the separator zone of the vessel chamber for discharging thecontaminants and free water that have settled therewithin; f. adischarge line in the upper filtration zone for discharging fluidintroduced into the vessel chamber; g. a primary filter medium containedwithin the upper filtration zone of the vessel chamber above the upperbaffle for filtering fluid being discharged from the discharge line ofthe vessel chamber; and h. means within the tank portion for receivingdischarged fuel from into the tank under such a velocity so as to createa turbulence of fuel, free water and contaminants within the tank. 2.The vessel in claim 1, wherein the upper horizontal baffle allowscontaminants which may have reached the filtration zone within thevessel to move into the fluid flow bore down into the separator zone ofthe vessel chamber.